Electronic anti-intrusion device

ABSTRACT

An electronic anti-intrusion device having an electric noisemaker activated by an anti-disturbance switch, which is sensitive to specific physical movement, a mechanical switch for simultaneously energizing the device and unshorting the noisemaker after dispersal, an electronic timing circuit for delaying activation during a first interval of time and an electronic circuit for activating the noisemaker any time after the first interval of time regardless of whether the antidisturbance switch is in an open or closed position.

Dec. 19, 1972 United States Rand et a1.

References Cited UNITED STATES PATENTS 154] ELECTRONIQ ANTI-INTRUSION DEVICE ZOO/61.45 R

Hall et al..... .......340/276 396 Perelman 793 9/1970 Shottenfeld 114 4/1971 Quist et al... 632 4/1970 West et a1... 298 4/1970 Kirk............ 203 1/1971 Assignee: The United States of America as Primary Examiner-John W. Caldwell t d b the Secrets. of the Assistant Examiner-Glen R. Swann, III" 25;? e y y Attorney-Harry M. Saragovitz, Edward J. Kelly and Herbert Berl [57] ABSTRACT An electronic anti-intrusion device having an electric [22] Filed: Feb. 18, 1971 [21] Appl. No.: 116,362

noisemaker activated by an anti-disturbance switch, which is sensitive to specific physical movement, a mechanical switch for simultaneously energizing the device and unshorting the noisemaker after dispersal, an electronic timing circuit for delaying activation during a first interval of time and an electronic circuit [52] 11.8. C|.........200/6l.52, 102/70.2 R, ZOO/61.11

340/276, 340/282 .H0lh 35/02, HOlh 35/14 [51] Int.

[58] Field of Search..............40/282, 283, 276, 52 H;

200/6152, 61.11, 61.45 R, DIG. 29'

for activating the noisemaker any time after the first interval of time regardless of whether the antidisturbance switch is in an open or closed position.

1 Claim, 3 Drawing Figures ELECTRONIC ANTI-INTRUSION DEVICE GOVERNMENT INTEREST The invention described herein may be manufactured, used and licensed by or for the Government for governmental purposes without the payment to us of any royalty thereon.

BACKGROUND OF THE INVENTION The present invention relates to a time delay fuze and has particular reference to an electronic anti-intrusion device which may be mechanically dispersed over an area for which constant surveillance is desired.

Problems have. been encountered in the aerial and mechanical delivery of mines and anti-intrusion devices because of premature activation of the anti-disturbance mechanism of the device prior to their reaching the intended target area, thus, destroying their subsequent effectiveness either as a warning device indicating the presence of intruders, or as a defensive ordnance.

In order to overcome the aforementioned premature firing during delivery and loss of effectiveness, after delivery, prior art anti-disturbance time delay fuzes have used expensive mechanical delay armings means in combination with complex electronic timing circuitry. It is desirable to have an anti-intrusion device which can be dispensed by aerial means, ground mechanical devices, or manually, remaining safe and inoperative during the dispersal stage and operative after dispersal when the device is physically disturbed by an intruder. It is also desirable that the device remain armed and be insensitive to rain, wind, natural ground vibration, sonic booms and battlefield noises. It is likewise important that the device be small, so that it may be easily camouflaged to blend in with its surroundings so that it may not be readily detected.

SUMMARY OF THE INVENTION The present invention is an electronic anti-intrusion warning device which is capable of being safely delivered to a target area either by aerial or ground mechanical means. The aforementioned present invention is non-responsive to inadvertent movements of the device occurring during the delivery stage, or upon initial impaction with the ground or dense foliage. The electronic anti-intrusion device described herein will become armed after reaching the ground and will emit an electronic warning, or detonate when the device is pushed, kicked, picked up or physically disturbed by an intruder by any other means. The present device because of its simplicity may be enclosed in a cylindrical shape of approximately one inch diameter and 0.4 inches high.

One of the objects of this invention is to provide an electronic anti-intrusion device which is reliable, small in size, and adaptable to large-scale production methods.

Another object of this invention is to effectively detect the presence or movement of personnel in a given ground area under all weather conditions and under poor lighting conditions.

Another object of this invention is to provide an electronic anti-intrusion device which will remain inoperative while being dispersed and become operative after reaching the intended delivery area.

Another object of this invention is to insure the operation of an anti-intrusion device after an initial time delay that may vary from seconds to days.

Another object of this invention is to insure operation of an electric warning device or detonator whenever the device is physically moved subsequent to dispersal.

Another object of this invention is to provide a sensitive anti-disturbance switch in combination with an electronic circuit and electric detonator which will be responsive to kicking, pushing, being picked up or other physical movements but will not be responsive to rain, ground vibrations, sonic booms, and battlefield noise.

Another object of this invention is to provide an'antiintrusion device which is not dependent upon a mechanical time delay to remain inoperative during the dispersal period.

A further object of this invention is to insure operation of an anti-intrusion device regardless whether the anti-disturbance switch after dispersal is in the open or closed position.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of the electronic circuitry for the anti-intrusion device.

FIG. 2 is a partial sectional view of the antidisturbance switch used in the device illustrated in FIG. 1 and FIG. 3 along line 2-2.

FIG. 3 is a sectional view taken along line 3--3 of illustration shown in FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, while the anti-intrusion device is in storage and before being dispersed, the device is maintained inoperative by the mechanical short-start switch S1. Switch S1 shorts out the electric noisemaker 24, by connecting the electrical conductors 25 and 27 across points 15 and I7 and disconnects the power source 10 from the remaining circuitry. When the device is dispersed S1 is moved from the closed contact NC to the open contact NO removing the short across electric noisemaker 24 and electrically connecting the power source 10 to the load circuitry 12 at points 15 and 16 through a series limiting resistor 13. During a first interval of time that the anti-intrusion device is falling, and until it has settled on the ground, the silicon controlled rectifier I9 is prevented from conducting sufficient current from anode lead 18 to cathode lead 22 by an electronic delay consisting of a load capacitance 14 and series limiting resistor 13. The load capacitance 14 has its terminals in parallel with series connected silicon controlled rectifier 19 and electric noisemaker 24 and is prevented during this first interval of time from reaching the minimum charge necessary to activate the electronic noisemaker 24. The noisemaker 24 will remain inactive during this first interval of time even though the anti-disturbance switch first contact lead 28 and a plurality of second contact leads 30, 30 have intermittently opened and closed delivering a triggering pulse at point 31 to the trigger electrode 20 of silicon rectifier 19. A plurality as used hereinafter is defined as one or more. The triggering pulse is generated by a pulse forming circuit which consists of a parallel combination of pulse capacitor 34 and pulse resistor 32 which is electrically coupled to the silicon controlled rectifier trigger electrode 20 by antidisturbance switch S2. While this triggering pulse is sufficient to cause the silicon controlled rectifier 19 to conduct, during dispersal it will not activate the electric noisemaker for the aforementioned reasons. When the anti-disturbance switch S2 has its contacts 28 and 30, 30' in the open position and switch S1 in the opened position NO the trigger electrode 20 will be biased to cut off by biasing resistor 26. Thus, during this first interval of time, the anti-disturbance switch S2 may randomly open and close contacts 28 and 30, 30', triggering silicon controlled rectifier l9 and discharging load capacitance 14 without activating electric noisemaker 24.

However, once the anti-intrusion device has settled on the ground and the aforementioned first interval of time has elapsed, voltage will build up across load capacitance 14 terminals at points 15 and 16 sufficient to charge it with enough energy to activate the electric noisemaker 24 whenever the silicon controlled rectifier 19 receives a triggering pulse. After settling the contacts of mechanical switch S1 will remain in the open position NO, the anti-disturbance switch S2 after this first interval of time, may be either in the open position as shown in FIG. 1 or in the closed position. Any time after this first interval of time the silicon controlled rectifier 19 will be maintained in the cut-off, non-conducting state, by the voltage developed across the bias.- ing resistor 26. However, any motion given to the antiintrusion device as a result of pushing, kicking, or picking up which changes the position of S2 from either a closed state where contact lead 28 is touching contact leads30, 30' to an open position as shown in FIG. I, which subsequently causes closure of the aforementioned contacts 28 and 30, 30 or where the contacts were open to a closed position, will result in a transient discharge to trigger electrode 20, causing the silicon controlled rectifier 19 to conduct and thereby discharge the energy stored in the load capacitance 14 to the series electrically coupled electric noisemaker FIGS. 2 and 3 show the details in a partial cross-sectional of the anti-disturbance switch S2 schematically illustrated in FIG. 1. A first lead 28 and a plurality of second leads 30, 30 are held in a longitudinally oriented position in a flanged-header cup 40 by an insulator 38. The first lead 28 is fixed at one end to the flanged header cup 40, the other end of lead 28 is fixed to point 31 as illustrated in FIG. 1. The plurality of second leads 30, 30' are electrically isolated from the header cup 40 and protrude on one end through a plurality of small orifices 43, 43 on the closed end'top surface 44 of header cup 40. Leads 30, 30' are operatively positioned in flanged header cover 42 so that the distance from the peripheral edge of these leads nearest the inner surface 48 is less than the diameter of balls 50, 50'. The other end of leads 30, 30' are connected to point 33 as illustrated in FIG. 1. A flanged header cover 42 is circumambient to the top surface 44 of the header cup 40 and to the first end of lead 30, 30. The enclosed space 46, formed by the separation between theinner surface 48 of the flanged header cover 42 and the top surface 44 of header cup 40, provides a restrained area for movement of a plurality of contact balls 50, 50

either top surface 44 or inner surface 48, to touch or not to touch the second leads 30, 30, thus either closing the electrical contact between lead 28 and 30, 30' of anti-disturbance switch S2 if they were previously open, or opening the electrical contacts if they were previously closed. Such opening or closing of contacts between leads 28 and 30, 30 after a first interval of time will result in a transient pulse being delivered to the trigger electrode 20, followed by conduction of the silicon controlled rectifier 19, and passing of energy from the fully charged'load capacitor 14 to activate the electric noisemaker 24.

From the above description it will be evident that the invention provides an anti-intrusion device which can be air dropped, mechanically dispersed, or manually implaced, remaining safe and non-operative during a first interval of time corresponding to the dispersal time, which will not activate upon impact with the ground or other hard surface, during this first interval of time but will become operative after this first interval of time when subjected to a specific type of disturbance as aforementioned.

We wish it to be understood that wedo not desire to be limited to the exact detail of construction shown and described for obvious modifications will occur to a per- 5 son skilled in the art.

What is claimed is:

1. An anti-disturbance switch which comprises:

a flanged header cup having a plurality of orifices in a closed end wall and a flanged rim on an open end;

an insulator partially filling said header cup;

a first contact lead, longitudinally held in said insula tor, having one end fixed to an inner surface of said closed end and the other end partially protruding out of said open end;

a plurality of second contact leads each longitudinally held in said insulator aligned within one of said orifices partially protrudes through said header cup closed end wall and partially protrudes through said open end, said insulator electrically isolates said plurality of second contact leads from said header cup;

a flanged header cover having a closed end wall and a flanged open end larger than said flanged header cup', and positioned circumambient to said flanged header cup forms an enclosed space; and

a plurality of contact balls located within said enclosed space free to roll when said anti-intrusion device is moved, causing said first and said plurality of second leadcontacts to be electrically connected when said plurality of contact balls simultaneously touch said plurality of second contact leads and said header cup top surface. 

1. An anti-disturbance switch which comprises: a flanged header cup having a plurality of orifices in a closed end wall and a flanged rim on an open end; an insulator partially filling said header cup; a first contact lead, longitudinally held in said insulator, having one end fixed to an inner surface of said closed end and the other end partially protruding out of said open end; a plurality of second contact leads each longitudinally held in said insulator aligned within one of said orifices partially protrudes through said header cup closed end wall and partially protrudes through said open end, said insulator electrically isolates said plurality of second contact leads from said header cup; a flanged header cover having a closed end wall and a flanged open end larger than said flanged header cup, and positioned circumambient to said flanged header cup forms an enclosed space; and a plurality of contact balls located within said enclosed space free to roll when said anti-intrusion device is moved, causing said first and said plurality of second lead contacts to be electrically connected when said plurality of contact balls simultaneously touch said plurality of second contact leads and said header cup top surface. 